Oil Reserves Growth Potential

Transcription

1 Oil Reserves Growth Potential F. Harper ASPO 4 Berlin, 5 th May 4

2 Reserves Growth The amount by which initial estimates of the reserves in a field or population of fields will (or are expected to) grow with time It is important to distinguish between growth in different categories of reserves (eg proved vs. proved and probable) or under different reporting regimes (eg US vs UK) What are the sources of growth? How do you measure it? What is it s magnitude?

3 Reserves Growth Prudhoe Bay Daily Proiduction (mbpd) bnbbl to 13.5 bnbbl Actual and Forecast Planned 1977 Original Reserves Original Proved Reserves (bnbbl) Reserves Growth is: Typically a factor in mid to late field life Expensive Measured by comparing prediction with actual

4 Reserves Growth More Fields Reserves multiplier Gyda Ula Miller Harding Endicott Pt McIntyre Mars Pompano Years since start Production Reserves Growth is: Variable (and may be negative) Not necessarily restricted to late field life More difficult in deepwater environments

5 Sources of Reserves Growth Addition (Shallower Pool) Revisions/ Improved Recovery Addition (Satellite) Extension (Structural) Extensions/Additions = Increased In-place Revisions/Imp. Rec. = Increased Recovery Extension (Stratigraphic) Addition (Deeper Pool)

6 Reserves Growth is: A combination of in-place and recovery changes Often attributed primarily to recovery increase since in-place volumes are studied less frequently The Roles of In-Place and Recovery In-Place Volumes multiplier Gyda Ula Miller Harding Endicott Pt McIntyre Mars Pompano Recovery Factor multiplier ; Years since start Production Years since start Production

7 Combining In-place and Recovery effects Recovery Factor Multiplier Reserves Growth No Growth Gyda Ula Miller Harding Endicott Pt MacIntyre Mars Pompano.5 Reserves Decline Oil-in-Place Multiplier

8 Year of Discovery EIA discovery estimates for L Year of Estimate Data from EIA database to 91 (Attanasi & Root 94)

9 EIA estimates Arrington approach Year of Estimate st year revision th year revision Data from EIA database to 91 (Attanasi & Root 94) Year of Discovery

10 Reserves Growth USA Oil Cumulative Revision Ratio st year revision th year revision Years since initial discovery 14 year Avg '77-'91 Rapid growth in the first few years, then slows Growth continues to 6 years (and beyond) Cumulative revision ratio about 1 Data from EIA database to 91 (Attanasi & Root 94)

11 Reserves Growth USA Oil 9 Discovered Volume (mmbbl) Original Grown A Cumulative Revision Ratio of 1 over 65 years Growth = bn bbl (Compare with Proved Reserves of 4 bn bbl)

12 Reserves Growth USA Oil Cumulative Revision Ratio st year revision th year revision More growth for older years of study, Less growth for more recent years Years since initial discovery 14 year Avg '77-'91 7 year Avg '77-'84 7 year Avg '84-'91 Data from EIA database to 91 (Attanasi & Root 94)

13 Proved Reserve Additions USA Oil Reserve Adds (mmbbl) Revision Addition Extension Discovery Revisions % 8% 7% 6% 5% 4% 3% % 1% % -1% Data from EIA annual reports Revisions % on a 3-year rolling average

14 Oil Reserves Changes by Field - UK 1.8 Reserves Change Factor Average. Changes to reserves since development approval Years since Annexe B Data from DTI annual Brown Book reports

15 Oil Reserves Changes by Field - Norway 1.8 Reserves change Factor Changes to reserves since development approval Average Years since Development Approval Data from NPD annual White Book reports

16 IHS and OGJ Remaining Reserves OGJ Reserves IHS Rpt Data from IHS Energy and OGJ annual reports

17 IHS and OGJ Remaining Reserves OGJ Reserves 1995 IHS Rpt 1996 IHS Rpt 1997 IHS Rpt 1998 IHS Rpt 1999 IHS Rpt IHS Rpt 1 IHS Rpt IHS Rpt 3 IHS Rpt Data from IHS Energy and OGJ annual reports

18 Growth in IHS Original Reserves World Growth to 199 Cum Reserves Rpt 1994 Rpt 1995 Rpt 1996 Rpt 1997 Rpt 1998 Rpt 1999 Rpt Rpt 1 Rpt Rpt 3 Rpt Data from IHS Energy annual reports

19 Growth in IHS Original Reserves FSU Growth to 199 Cum Reserves Rpt 1996 Rpt 1997 Rpt 1998 Rpt 1999 Rpt Rpt 1 Rpt Rpt 3 Rpt Data from IHS Energy annual reports

20 Growth in IHS Original Reserves MidEast Growth to 199 Cum Reserves North Field Rpt 1996 Rpt 1997 Rpt 1998 Rpt 1999 Rpt Rpt 1 Rpt Rpt 3 Rpt Data from IHS Energy annual reports

21 Growth in Global Oil Reserves Cumualtive Revision Ratio Arrington approach Based on 11 year average 93-3 Annual Discoveries (bnbbl) Years after Discovery Data from IHS Energy

22 Growth in Global Oil Reserves Cumualtive Revision Ratio Arrington approach Based on 11 year average 93-3 Annual Discoveries (bnbbl) 1?"Grown" Data 9 adds ca. 35 bnbbl? Years after Discovery Data from IHS Energy

23 Growth in Global Gas Reserves 3.5 Analysis in 1 5 Based on 5 year average Cumualtive Revision Ratio.5 Actual Data Power Law Model Annual Discoveries (tcf) Years after Discovery Data from IHS Energy

24 Growth in Global Gas Reserves 3.5 Analysis in 1 5 Based on 5 year average 97-1 "Grown" Data Adds ca. 5tcf 3 4 Cumualtive Revision Ratio.5 Actual Data Power Law Model Annual Discoveries (tcf) Years after Discovery Data from IHS Energy

25 Growth in Global Gas Reserves 3.5 Analysis in 1 5 Analysis in 3 Cumualtive Revision Ratio Based on 5 year average 97-1 Actual Data Power Law Model Cumualtive Revision Ratio Based on 7 year average 97-3 Effect of growth in North, S.Pars Years after Discovery Years after Discovery Data from IHS Energy

26 Conclusions Reserves estimates are uncertain and can vary widely throughout field life. There is a general tendency for reserve estimates to grow; this is true both for P preserves where the primary driver may be technological development and increased spend and for proved reserves where an additional driver may be reporting conservatism. Growth functions for any reserves dataset should be derived from within that dataset and should not be applied to others. Growth occurs by a combination of adding new oil-inplace and increasing recovery factor (and by underreporting/back-booking for groups of fields) Growth is measured by comparing forecast and actual or by tracking annual estimates of historical discoveries. Reserves growth is a potentially important component of the oil resource but its magnitude is poorly known.